YUMA, Ariz. - President Bush Monday argued that because border security measures enacted by Congress last year are beginning to work, it is now time for lawmakers to pass his stalled comprehensive overhaul of the nation's immigration laws.

"It is a matter of national interest and it's a matter of deep conviction for me," the president told federal agents and their families gathered here for the grand opening of the U.S. Border Patrol's new Yuma Station Headquarters.

"I've been working to bring Republicans and Democrats together to resolve outstanding issues so that Congress can pass a comprehensive bill and I can sign it into law this year."

Immigration is the rare issue where the November Democratic takeover of Congress may help the embattled Republican president score a major policy victory.

Last year, the Senate approved a bill along the lines of Bush's plan that included a temporary worker program and an eventual opportunity for longtime illegal immigrants to pay a penalty and then become legal residents.

But Republicans in the House, some believing they had a silver-bullet election issue, refused to go beyond border security.

Rep. Jeff Flake, R-Arizona, an advocate of a comprehensive approach, said enforcement-only sentiment still runs high among House Republicans. But he said that enough Republicans were chastened by last year's electoral drubbing that they will be more open to the president's plan this year.

"Last year, we ginned up the issue and we paid the price for it in November," Flake said.

Whether enough Republicans will sign on is highly uncertain.

Rep. Brian Bilbray, R-Calif., said in a statement that he supports the president's goal of passing "true" immigration reform legislation by year's end, but his opposition to the president's plan remains strong.

"Ultimately, the devil is in the details - the president and Congress need to remember what part of illegal in illegal immigration do people not understand?" said Bilbray, who was elected last year espousing a hard line on illegal immigration.

Among other things, Bilbray advocated tougher penalties for people who hire illegal immigrants.

Bush recalled that he visited Yuma last May at a time when illegal immigrants were streaming across the U.S.-Mexico border and there was little that a severely understaffed Border Patrol could do to stop them. Since then, the White House said, apprehensions along the 125-mile Yuma sector are down 55 percent because of increased manpower and new equipment.

"Back at this site, there's now infrastructure, there's fencing," the president told his audience Monday. "And the amount of people trying to cross the border at that spot is down significantly."

"That's what I'm down here for, to remind the American people that we're spending their taxpayer - their money, taxpayers' money, on securing the border. And we're making progress," he said. "This border should be open to trade and lawful immigration, and shut down to criminals and drug dealers and terrorists and coyotes and smugglers, people who prey on innocent life."

After the speech, Arizona Gov. Janet Napolitano, a Democrat, agreed that progress had been made, but said that much more needs to be done.

"It's not getting better with time. And so we need the Congress to buckle down and get a bill done that is comprehensive, that includes the elements the president spoke of today," Napolitano told reporters. "All of these border security systems that we've been talking about today need to fit into a comprehensive system that makes sense."

Bush's appearance near the Mexican border comes as his administration is trying to rally congressional Republicans behind legislation that would both provide legal status for millions of immigrants now in the country and establish channels for future flows of guest workers.

Most Democrats are prepared to embrace the sort of sweeping legalization detailed in a bill passed last year by the Senate and outlined in a bill proposed last month in the House of Representatives.

But a large majority of Republicans, joined by some Democrats from districts reeling under the strains of new flows of illegal immigration, have balked at any program that would provide permanent legal status to illegal immigrants.

Their fear is that such a program would encourage more illegal immigration, especially if enforcement both at the border and at the workplace is not tough enough to discourage illegal flows across the border.

Bush's appearance in Yuma was an attempt to close that divide by signaling his administration's determination to avoid the surge in illegal immigration that followed the now-infamous 1986 amnesty legislation.

Bush said a comprehensive approach - combining legal status with stepped up enforcement - is the only way to solve a problem that has been growing at the rate of nearly a half million more illegal immigrants every year.

After Bush's speech, House Speaker Nancy Pelosi urged him to embrace legislation recently introduced in the House. It would not only provide legal status to most of the 11 million or 12 million illegal immigrants estimated to be in the country but also provide a path to citizenship for hundreds of thousands of mostly low-skilled workers who could be brought in every year.

"We must enact immigration reform that is humane and honors our American tradition of being a nation of immigrants," said Pelosi, D-Calif.

Meanwhile, immigrant advocates have expressed outrage at proposals floated by the administration last week. One idea is for illegal immigrants currently in the country to be allowed to seek three-year visas that would be renewable at a cost of $3,500.

That idea, Eliseo Medina, executive vice president of the Service Employees International Union, said Monday, "would leave many workers, such as those in the construction, child care, and service industries, little choice but to remain in the shadows."

According to the nonpartisan statewide poll, a solid majority favors legalizing the status of longtime illegal residents. The poll also found that while voters favor stepped-up enforcement efforts, there is growing opposition to building walls along long stretches of the border.

Monday, Bush again took exception to the contention of Republican opponents of his plan that he is promoting "amnesty." Bush wants illegal residents to earn their way toward citizenship by paying a fine, paying any back taxes that are owed, learning English and getting in line behind people who already have applied for citizenship.

"People who entered our country illegally should not be given amnesty," he said. "Amnesty is the forgiveness of an offense without penalty."